Treatment of polyolefin articles and resulting products



y symptom? bio Drawing.

This invention relates to the treatment of polyoletin articles and to the resulting products. More particularly. it concerns modification of preformed fibers, films and other shaped articles of solid polymers of olefins to im prove surface characteristics including improved dye receptivity, reduced static electricity propensities and greater adhesion to coatings.

High molecular Weight polymers of ethylene, propylene and other olefins have been developed which possess a wide range of desirable properties and other attractive features, including low cost. These high molecular Weight polymers have become of great commercial importance because of their low cost and many attractive properties. The low-cost, high-strength plastics are being molded. extruded or otherwise fabricated into thousands of dif- Jfcrent types of household and industrial articles, and they have generated many new industries for the fabrication and utilization of plastics.

Fibers and films constitute a major use of the high molecular weight polyolefins. Fibers constitute a con templated enormous outlet for the polyolefins which are expected to find ever increasing use in the production of carpets or other floor coverings, yarns and fabrics for Wearing apparel, furniture and seat covering and every other use for textile fibers and fabrics which employ large quantities of filaments or yarns.

The widespread use of polyolefins and contemplated further expansion thereof is due to certain inherent at tractive properties of the polymers. including high-strength, resistance to attack by insects, mildew or molds and high resistance to corrosion or attack by cleaning agents, light or other chemical or physical agents. However, these inherent properties of the polyolefins also present some problems. Thus, the high degree of chemical incrtness of the polymers, although a distinct advantage from some viewpoints, is a disadvantage with respect to the coloring or coating of the polymers. Since the polymers are so inert to most chemical agents, shaped articles made there from cannot be dyed, colored or coated satisfactorily using conventional dyeing and coating materials and techniques. As a result, a tremendous amount of research and develop ment worlt has been devoted to attempts to surmount the coloring and coating problems associated with the high molecular Weight polyolefins. To date, the difficulties of dyeing and coloring the polymers have materially rcstricted their use and will continue to restrict the commercial markets and fields of applications of the polyolcfins until satisfactory methods of coloring and coating these materials are developed.

Another inherent disadvantage of solid polymers of olefins is their tendency to acquire static electrical charges. Such static propensities are particularly troublesome in the use of the polyolefins for films and fabrics. This disadvantage is particularly pronounced with carpeting made of olefin fibers and results in the annoying sparking" which can occur from wallting across a floor covering made from yarns of olefin fibers. The static prob- 1cm can be mitigated to some extent by applyingwarious anti-static agents to the fibers or fabrics made lhcrcof, but such treatments are not durable to many cleaning operations.

A principal object of this invention is the provision of new processes for treatment of preformed articles of [ill surfaces f preformed nrtic r of solid polyolcfins so as to obtain greater adhesion l much surfaces and coatings that are applied to th (4) The provision oi new pri. .ndcring fibers, films or other preformed art of c has which are normally subs able olf being satisfac orily dyed. capable in shades With com cntional dycing metl t 5) The provision of new method for dyeing or otherwise coloring prclormcd artit ot' lid no .lins that deep coiwcntional may be carried out in equipment convcntitmully aimilablc and which can be used in conitmc. .l with conventional, commercially available cationic d tull's for m parable coloring materials and established dyeing p. coloring procedures.

(ii) "the prrwision of new. improved forms ot preformed articles of olid surface characteristics a i.:ompart it related articles of the solid polynmrs.

(7) The provision of new and in fabrics, films and other shaped s i mers of olcfins having improvct static electricity propensities and grcatm adhesion to resinous or other coatings applied to the surfaces of the preformed articles.

(8) The provision of nevi prt'rccdnrcs for increasing the adhesion of laminated resins to polyolctin films, tabrics or other polyole fin articles.

(9) The pro sion of new metli ability of polyolcfins to retain rnents and other coat J, 3 lini be applied to the Other objects and further I present invention will become description given hereinaifx however. that the detailed dc a a glica ity of the -nt from. the detailed hould be and, .ood, prion and specific eita '.l-- cn'tbodiments ol the in vcntion, given by way 0 ustration onl since vari ous changes and modifications Within the spirit. and scope of the invention will bcconn' nt to those sltilled in the art from this detailed r' tron.

These objects are accomplished accordir", to the present invention by the treatment of preformed articles of solid olefin polymers with an organic phosphoric acid, particularly the organic phosyg'ihoiic acids having the following structural formula:

lyolcfin article with the organic phosphoric acid is carr out so as to cause a small amount of the or; 1 a "torn: acid to become permanently associated i. it the it f the polyolefin article. Such treatment can l but. pt'ClCl'FllJlj/ this is iiccon lace ol the y iolyolclin article i ous Ways,

acid, and then, while the article is in contact with the acid, heating at least the surface of the article to an elevated temperature for a time sufficient for at least some of the organic phosphoric acid to become permanently associated with the article surface. Following such treatment, any excess of the organic phosphoric acid which has not become permanently associated with the polyolefin article is removed such as by scouring the article, leaving the article with improved dye receptivity and other surface characteristics, but otherwise unchanged in visible appearance, strength characteristics or other desirable properties.

The contacting of the polyolefin fibers, films or other preformed solid articles with the organic phosphoric acid may be accomplished While the phosphoric acid is in the vapor or liquid form including solutions in organic solvents, aqueous dispersions or emulsions, as a component of a molten bath, or from solubilizing systems using salts of the free acid or other compounds which yield the free acids under the conditions of treatment. The application of the organic acid can be by impregnation, spraying, coating, contact with vapor or liquid bath, or any other suitable fashion. Following such contact of the reagent with the polyolefin article, the structure is heated to an elevated temperature of about 100 C. or higher, but at least about C. below the melting point of the polyolefin. The times of heating will vary inversely with the temperature so that the heat treatment may be effected in a few minutes at high temperatures up to several hours at low temperatures.

According to a preferred embodiment, a two-step procedure for coloring preformed articles of olefin polymers involves first treatment of the article with organic phosphoric acid followed by dyeing or other coloring or coating of the surface of the article. In the case of textile materials, the modified, treated fabric may be colored by padding through a bath of basic dyestutf followed by drying of the colored material. Alternatively, the modified textile material may be printed with dye-printing systems utilizing conventional techniques.

The basic treatment as outlined above may be moditied with preliminary, simultaneous or subsequent auxiliary processes and agents including wetting agents, leveling agents, thickening agents, anti-croclting agents, emulsifiers, water-repellents, oil-repellents and the like. Depending on the concentration of organic phosphoric acid employed, which will be used broadly in amounts of 0.1 to 100% by weight of the polyolefin being treated, the preformed modified article may be used directly for subsequent coating, dyeing or other surface treatment or may be scoured or otherwise processed to remove excess of the organic phosphoric acid.

The success of the present invention is due in part to the discovery that the treating agent used for modification of the surface of the preformed polyolcfin article produces a permanent improvement in the surface characteristics of the article that is permanent. In other words, the change in the article surface creating improved dye receptivity, reduction in static electricity propensities, etc., is not removed by washing, scouring. dry-cleaning. or other normal handling or processing operations to which fibers, films or other preformed articles of polyol'cfins would be subjected. On the other hand, these treatment procedures do not visibly effect the preformed articles nor detract from the strength or other desirable properties of the articles. Whether partial or complete penetration of the treating reagent into the fibers, films or other articles takes place is presently not known. in any event, the results of the treating procedures contrasts greatly with known behavior of surface coating Where the color or other cffeet obtained by the coating is easily removed by rubbing, by wear or by washing and dry-cleaning processes.

The following list is exemplary of organic phrosphoric acids which may be used in treating polyolefin articles in accordance with the invention. Mixtures of two or more organic phosphoric acids may be used in the procedures of a plurality of such reagents may be applied in separate treating steps.

Propyl phosphoric acid Butyl phosphoric acid Diumyl phosphoric acid Octadccyl phosphoric acid Glycerol phosphoric acid Di-Zcthylhexyl phosphoric acid Phenyl phosphoric acid Methyl phcnyl phosphoric acid Dioctyl acid phosphate Propyl diacid phosphate Benzyl diacid phosphate Butyl lauryl acid phosphate Benzyl phenyl phosphoric acid Cyclohexyl phosphoric acid Naphthyl phosphoric acid p-Hexylphenyl methyl phosphoric acid Z-phenylethyl octadecyl acid phosphate A further understanding of the new procedures and resulting products of this invention may be had by reference to the following specific examples of actual operations in accordance with the invention. In these examples and throughout the remainder of the specification and claims, all parts or percentages are by weight unless otherwise specified.

Example 1 A film of polypropylene was passed through a solution containing 5 parts of butyl phosphoric acid and 95 parts of isopropanol. 1t was then air dried and heated at 105 C. for minutes. After heating, the film was scoured in a water solution containing 0.1% non-ionic detergent and 0.5% sodium carbonate, rinsed and dried. The piece of treated polypropylene film and a piece of the original film similarly treated with isopropanol alone were dyed together in a dye bath containing 1% of the textile dye. Crystal Violet, based on film weight, and at a :1 bath ratio of solution to film weight. The dye bath was raised from 27 C. to 95 C. in one hour, held at 95 C. for another hour, then discarded. The dyed films were scoured in a bath containing 0.1% non-ionic detergent and 0.5% sodium carbonate at C, rinsed several times and dried. Examination of the two films showed that the one pretreated with the butyl phosphoric acid solution was colored a very deep violet color, was opti cally clear, and produced no static charge on rubbing. The isopropanol treated film was essentially non-colored and only a very faint hue could be observed on close examination. This film readily acquired a charge of static electricity on rubbing.

Example 2 A solution containing 5 parts of butyl acid phosphate dissolved in parts of isopropanol was prepared. Using a conventional padding procedure, the solution was applied to samples of white cloth woven from continuous filaments of pol propylene and also other samples woven from spun yarns of polypropylene fibers. After padding, the Wetted specimens were dried for 15 minutes at C. followed by further heating for 5 minutes at C. The cloth specimens were then scoured with a cleaning solution containing 0.1% or" a non-ionic detergent and 0.25% sodium carbon dissolved in water. Finally, the scoured specimens were rinsed in clear water and dried at room temperature. The treated cloth specimens and comparable size pieces of the same types of untreated woven fabrics were dyed in a dye containing 1% Victoria Green based on fabric weight using a fabric/bath ratio of 1:30. The bath temperature was raised from 27 C. to 95 C. in one hour, and dyeing was continued for one hour more at the latter temperature. After dyeing, all the specimens were scoured in a cleaning solution consisting of 0.1% non-ionic detergent and 0.5%

sodium carbonate dissolved in water. Finally, the scoured specimens were rinsed and dried at room temperature.

All of the cloth swatches which had received the treatment with the organic phosphoric acid were colored a deep green and this color was level across the entire area of the swatches. lin contrast, the cloth swatches which had not received the pretreatment with the organic phosphoric acid were found to have only a faint green tint. The darh green cloth specimens we suhjectcd to lurther washing operations and to dry charting. lit was lound that these additional washing and cleaning operations did not appreciably ellect the color of the cloth specimens.

Example .i

The operations of Example 2 were repeated using a treating solution containing parts of octylphenyl acid phosphate dissolved in 95 parts of isopropanol. Similar results were obtained as reported in Example 2.

in yet another case, the procedure of Example 2 was repeated using a treating solution containing 5 parts of octadccyl acid phosphate dissolved in 95 parts of butanol. Again, substantially the same results as reported in lEJo ample 2 were observed with the cloth samples treated with the phosphoric acid being deeply green colored and being resistant to vigorous washing and dry-cleaning operations.

Example d Swatches of fabrics woven in plain weave from twisted yarn formed of polypropylene staple fibers were padded through the following isopropanol solutions:

(A) llsopropanol only lid) 1% stearyl acid phosphate (C) 2% stearyl acid phosphate ill) 3% stearyl acid phosphate (l5) 4% stearyl acid. phosphate (P) 5% stearyl acid phosphate The padding was carried out to give shout lllll% piclo up. The impregnated swatches were air dried tor one hour at room temperature and were then heated for minutes at 120 (I. Then, they were all scoured with a cleaning solution containing 8.1% non-ionic detergent and 0.2"J'% sodium carhonate dissolved in water. This was followed by three water rinses and an air drying. The swatches were then divided into five separate groups, each group being dyed with one ot the following five dit tcrent cationic dyes:

Victoria Green WlEt -JCJLWOJKZOOO Basic Green C.ll.l"-lo. l-2 l l-tl Basic lted C.l.l-lo.4250ll llasic Blue tlll.hio.5lltl l lCalcozinc tiled Cl. No. 50240 Dye baths were used containing 1% of the dye based on the weight of the fabric and dyeing was conducted with a bath/fabric ratio of 30:1. The swatches were immersed in the respective dye bath at room temperature. The bath was then raised to 95 C. in one hour and dye ing was continued for one hour at 95 C, after which the swatches were removed and scoured in a cleaning so-- lution. The resulting cloth samples were all dyed a level deep shade of the color of the dye used.

Example 5 Swatches of cloth woven of spun yarns ol? polypropylone fibers treated with 5% butyl acid phosphate as in Example 2, were scoured after heating for 5 minutes at 120 C. with the following scouring solutions:

(ft) 0.1% non-ionic detergent and l% copper acetate. (l8) 0.1% non-ionic detergent: and 1% chromium acetate.

After the scouring, the swatches were dyed as in 1E1;- arnple 2. The use of the metal salts in the scouring solution prior to dyeing produced improved leveling of the green dye.

ill

ill

till

till

til Tn another case, sample scoured a in Tirtnmp tamplc dyc .tirtin ll.) stc (Ill 3% polyamine-copper chloride nddnct (l) 3% nine acetate T hcsc solutitms were lltttitltitl on lltW/ctl lv' hcntitnr and dry color value eating the l nhric :matlc of solid polymers of olchr ol'" the treatment, would not he would have a propensity to charges or would exhibit a lacl. r or other coatings which might he op oi. the articles. Those polynter" whi..l importance with re ct to new t class of solid polym that have an .tnl n of at least tilt and particularly those havio an i viscosity between about l .2 and ahout. l0. hercnt viscosity as used herein. in a solution of U2 grants cl u. lin at lfltl" C. The invention to the treatment oil' solid polyn'tct' on then o ms.

The various ty' nil: olelin L treated in accordance with t. described in the patent and ltincyclopcdia ot tlhcmical T .mcnt volume t'll llll, t rnont volume ll tilll, i

Tl 1 hoth to iomopol 'nters olclins with unsatura h iaahle materials resulting in solid capable oil heing satisfactorily of the general inertncss oi new procedures are oi pat t rnent of fiber-forming polyrn...

polyethylene, polypropylene or nth copolyrnr 2 carbon atom lFiloer Prod t defines o the liht dorming p olyrn m e r comp one. propy one or rnents oi? this invention are con nection with r l} ol tin :lihcrs a:

The organic pho: horic acid wh" ical treating reagent may he used in n more satisfactorily it is dissolve in some sur ah which may include organic solve up i solvents, l-ll carhon alltanols, diallr l the lilte. Various concentrations oli treating otnpound relative to the polyolehn may employed. lFor example, in a padding method of up ying the treating material from a solution, satislartory results may he old-- tainted by the dc osition oi shout ill to luy n of treating agent hose dupon the weight the Deposition oll' hclwe treating compound ..as been ion tiiarticttlarly usc tul. "v therc the operation us i in conjnnc dyeing of the lihcr or othc" '5 desired, lower concentrations or, 1' most economical to use. in go .ount o'lf e ing reagent deposited is tletcrn'nned by the th of shade of dyeing required or the degree of other change in our :lacc characteristic rctpurcd. The concentration oli the solution of treating reagent will lil the degree oi modification d tion of solution to he applied relative to the solutions of the treating reagent conch.

. range and pressure dyeing equipment.

ti to 100% are useable. Typically. concentrations of 1 to 5% produce satisfactory modification.

The treating solutions or other systems may include auxiliary agents such as heavy metal salts of organic acids, e.g., zinc, copper, nickel, cobalt and chromium salts of formic, aoetic or other lower monocarboxylic acids. Also, they may include reagents to improve wash fastness, light fastness or other aspects of the final products. Such auxiliary agents would, for example, include synthetic resins, e.g., acrylic resins, amino-aldehyde resins, vinyl resins as well as wetting agents, leveling agents,

emulsifiers, anti-oxidants, light-preserving agents or the like.

In order to effect a permanent association of the treating reagent with the polyolefin fibers or other articles, one should employ what may bereferred to as a heating or aging step. This may be accomplished by heating the article in contact with the treating reagent to elevated temperatures, e.g., 100 to 250 C. for a period of about 1 to 120 minutes, preferably, 1 to minutes, depending to some extent upon the degree of modification desired and other considerations. The higher the temperature, normally the less time is required for the predetermined degree of modification to be attained. Temperatures within the range of about 50 C. up to about 10 C. below the melting point of the polymer are useable. This aging phase of the treating methods may be effected by other ways than direct heating, e.g., flash diffusion of the treating agent under pressure or in the presence of superheated steam, steam distillation onto the surface to be treated, or boiling from suitable solvent solutions of the treating agents.

After the treatment of the polyolefin article with the treating reagent, it is normally desirable to remove surplus treating agent, i.e., any of the treating material which has not become permanently associated with the article. Such surplus agent removal, particularly in the case of fibers and textiles, is typically carried out by scouring the material to remove the loosely held treating reagent. For this purpose, conventional textile scouring techniques, drycleaning techniques or the like may be employed. Such cleaning procedures are generally followed by rinsing or drying, but the treatment procedure may be immediately followed by dyeing or printing steps without cleaning the surplus treating agent from the article surface. This is particularly true where surplus treating agents would have no detrimental effect upon dyeing, coloring, printing or subsequent coating compositions.

The dyeing of treated polyolefin fibers, fabrics, films or the like following the surface modification thereof may be carried out with cationic, amidic or comparable basic dyes in conventional manners common to the art of dyeing textile in machines such as the jig, beck, pad-steam The conventional dyeing assistants, such as level agents, wetting agents, alkali salts, dye fixing agents, copper salts, chromium salts, etc., may be used in the process to produce uniform dyeing or to improve light-fastness, wash-fastness or the like as desired.

The treatment of the polyolefin materials may be carried out in any suitable stage. For example, in the case of continuous filaments, the treatment with the organic phosphoric acids may be accomplished immediately after spinning. In the case of yarns made of spun staple fibers, the treatment can be effected before the yarns are formed by operation upon the staple fiber or after formation of the yarn. Alternatively, fabrics can be woven from untreated monofilaments or spun yarn, after which they can be subjected to the new treatments and then dyed, colored,

coated or subjected to other operations. This gives great flexibility to manufacturers and users of polyolefin fibers, films or other articles. For example, it enables the manufacturers of filaments and films to produce one commodity, rather than a whole series of modified materials, since, using the procedures of this invention, treatment of the polyolefin articles to make them receptive to dyeing or other coating operations can be conducted at the plant of the fabric manufacturer. Also, the new operations enables the textile processor or manufacturer to utilize the advantages of the new operations without making large investments in special processing equipment or in special training of personnel.

Modification of polyolefins by inclusion of tie treating reagents of the invention into the polymer before forma tion of the ultimate preformed article is contemplated.

The treatment operations of the invention may be used for modification of olefin fibers when they constitute a portion of blended fabrics, e.g., when the fabrics are woven in admixture with polyester fibers, nylon fibers, silk fibers, cotton fibers or the like. On the other hand, may be preferable to treat the olefin fibers prior to the weaving, knitting or other fabrication of the blended fabric, particularly where blended fabrics having multiple dye substantitive properties are to be processed.

For special applications, the treating reagent, may be applied simultaneously with the spinning, extrusion or other formation of the fibers, films, rods or the like. Again, use of about 0.1 to 5% of the treating agent relative to the total weight of the polyolefin material. s satisfactory to produce adequate dye receptivity, decrease in static electric propensities or the like.

The new treatments as above described make possible the coloration of fibers, films, rods, sheets and other pre= formed articles of solid olefin polymers with conven tional dyestuffs which normally do not adhere to or dye the polymer surfaces. Such surface modification of the olefin polymers also has utility in the use of printing inks, labeling and production of other decorative effects. In addition, the operations render the olefin polymer surfaces less electrostatic, more receptive to laminating adhesives, more receptive to pigments, paints and other coating compositions, more receptive to fluid-repellent agents and the like.

I claim:

l. A process of improving the dye receptivity of polypropylene fibers which comprises:

(a) providing a solution containing about 5 parts of octadecyl acid phosphate in about par propanol,

(/2) padding polypropylene fibers (c) drying the padded fibers for about about 90 (3.,

(d) heating the dried fibers at to 15 minutes, and

(e) scouring the treated octadecyl acid phosphate.

2. A process for improving the surface characteristics of a preformed article composed of solid olefin polymer which comprises:

(a) applying to said article an organic phosphoric acid having the following formula:

. for about five Ill 0 It-i-OH wherein (l) R is a radical selected from the group consisting of alkyl, aryl, alkoxy and aryloxy containing 2 to 20 carbon atoms, and (2) R is a radical selected from the group consisting of hydroxy, alkyl, aryl, alkyloxy containing 2 to 20 carbon atoms and aryloxy, (b) heating the article with the applied organic phosphoric acid to a temperature between about 10 C. below the melting point of said polyolefin and 106 C. to cause at least a part of said organic phosphoric acid to become permanently associated with said article, (a) removing from the resulting article those portions of the organic phosphoric acid which do not become 9 permanently associated with said article as a result of said step (b), and

(d) recovering the resulting modified polyolefin article having improved surface characteristics.

- 3. A process of improving the dye receptivity of olefin fibers which comprises:

(a) contacting the fibers with an organic phosphoric acid having the structure (I) as defined in claim 2, and

(b) heating the fibers while in contact with said organic phosphoric acid to a temperature between about C. below the meltnig point of said olefin fibers and 100 C.

4. A process of treating a preformed polyolefin article which comprises:

(a) contacting said article with an organic phosphoric acid,

(b) heating the article while in contact with the organic phosphoric acid to a temperature between about 10 C. below the melting point of said polyolefin article and 100 C., and

(c) freeing the treated article from surplus organic phosphoric acid.

5. A shaped article of solid olefin polymer having improved surface characteristics comprising an organic phosphoric acid permanently associated with its surface.

6. Olefin fibers possessing the ability of being dyed in deep shades with cationic dyes comprising an organic phosphoric acid associated with the surface thereof which will not be removed by scouring of the fibers.

7. A process of dyeing olefin fibers which are not receptive to dyes which comprises:

(a) contacting said olefin fibers with an organic phosphoric acid having the Formula I of claim 2,

(b) heating the fibers while in contact with said organic phosphoric acid to a temperature between 10 C. below the melting point of said article and 100 C. to effect a permanent association of said acid with the fibers,

(c) cleaning the fibers to remove therefrom organic phosphoric acid not permanently associated with the fibers, and

(d) dyeing the fibers with a dye selected from the group consisting of cationic dyes and aminated dyes.

8. A process of treating a preformed article of solid olefin polymer to:

((1) improve its dye receptivity,

(b) reduce its static electricity propensities, and

(c) increase its adhesion to coatings which comprises applying to the surface of the article an organic phosphoric acid having the Formula I of claim 2 and heating the article with said applied organic phosphoric acid to a temperature between about 10 C. below the melting point of the article and 100 C.

9. Fibers composed essentially of a homopolymer of an u-olefin of two to four carbon atoms and containing on the surface portions only thereof an invisible layer of an organic phosphoric acid having the Formula I of claim 2, said fibers being receptive to dyes and being capable of being dyed in level, deep shades with conventional dyestuffs using conventional dyeing methods.

10. Olefin fibers formed of solid olefin polymer that is normally non-reeeptive to dyes, which fibers have permanently associated with their surface an ionic organic phosphorous compound having the Formula I of claim 2 in such small amount that the fibers have substantially the same appearance, hand and strength charac teristics as such olefin fibers would have in the absence of said ionic organic phosphorous compound, said fibers being receptive to dyes and being capable of being dyed in level, deep shades with conventional dyestuffs using conventional dyeing methods.

11. A preformed article composed of solid olefin polymer having 2 to 20 carbon atom alkyl phosphoric acid on the surface thereof, said article not being changed in visual appearance by the presence of said alkyl phosphoric acid, the article possessing improved dye receptivity, reduced static electricity propensities and greater adhesion to resinous coatings than such article would possess in the absence of said alkyl phosphoric acid.

12. Fibers composed of solid polymer of a 2 to 4 carbon atom aolefin capable of being dyed in deep shades with cationic textile dyes comprising between about 0.01 and 10% by weight of an organic phosphoric acid of the Formula 1 of claim 2.

13. A film composed of solid polymer of a 2 to 4 carbon atom a-olefin having low propensity to accumulate static electrical changes comprising between about 0.01. and 10% by weight of an organic phosphoric acid of the Formula I of claim 2.

14. A process for treating a film of polyolefin which comprises:

(a) contacting the film with an organic phosphoric acid of the Formula I of claim 2,

(b) heating the film while in contact with the organic phosphoric acid to a temperature between about and 200 C. or a period of about 5 to 100 minutes, and

(c) removing organic phosphoric acid from the film which has not become permanently associated with the film as a result of step (b).

References Cited in the file of this patent UNITED STATES PATENTS 2,475,628 McSweeney July 12, 1949 2,631,997 Stewart Mar. 17, 1953 2,719,156 Benneville et a1 Sept. 27, 1955 2,831,840 Lindeboom Apr. 22, 1958 2,932,550 Walmsley Apr. 12, 1960 2,980,964 Dillte Apr. 25, 1961 2,984,634 Caldwell et a1 May 16, 1961 2,985,604 Koehler et a1. May 23, 1961 3,006,947 Lanham Oct. 31, 1961 3,036,052 Mier et al. May 22, 1962 3,039,840 Sawaya June 19, 1962 FOREIGN PATENTS 838,296 Great Britain June 22, 1960 OTHER REFERENCES Ham: Industrial and Engineering Chemistry, vol. 46, No. 2, pp. 390-392. 

2. A PROCESS FOR IMPROVING THE SURFACE CHARCTERISTICS OF A PREFORMED ARTICLE COMPOSED OF SOLID OLEFIN POLYMER WHICH COMPRISES: (A) APPLYING TO SID ARTICLE AN ORGANIC PHOSPHORIC ACID HAVING THE FOLLOWING FORMULA: 